[Leetcode] Remove Element

Given an array and a value, remove all instances of that value in place and return the new length.

The order of elements can be changed. It doesn't matter what you leave beyond the new length.

class Solution {
public:
/*algorithm
use two pointer: i pointer to source array, j point to dest array
copy i element to j array when i element is not val
time O(n), space O(1)
*/
int removeElement(vector<int>& nums, int val) {
int n = nums.size();
int j = 0,i = 0;
while(i < n){
if(nums[i] != val)nums[j++] = nums[i++];
else i++;
}
return j;
}
};